The recent development and production of conductive polymers has become significant due to the increased number of applications which incorporate the polymers. Such applications are related to, for example, electrochemical devices, chemical and optical sensors, and light emitting devices. Such polymers are important since they potentially display high room temperature conductivity, and can also exhibit superconductivity at reduced temperatures.
A number of monomers are used to form conductive polymers including, for example, sulfurnitride, acetylene and related derivatives, phenylene and related derivatives, and heterocycles such as pyrrole. Several processes are currently employed for synthesizing conductive polymers. One process typically involves providing one or more monomers in an organic solvent, along with a charge transfer or oxidizing agent and a dopant. The monomer is oxidized which forms a polymer in the solvent medium. In one of the conventional processes in conductive polymer synthesis, the oxidant is reactive in both the oxidation polymerization and a doping reaction. The oxidative agent essentially converts an insulating organic polymer to a conducting polymer with near metallic conductivity.
The use of organic solvents, however, is becoming disadvantageous. Specifically, these solvents are potentially environmentally hazardous. Additionally, other problems exist with respect to dispersion of dopant in the polymeric material. Moreover certain conductive polymers, e.g., polypyrrole and polyaniline, tend to be largely insoluble in organic solvents, thus restricting their application in traditional processing operations.
In view of the above, it is an object of the present invention to provide a method of forming electrically conductive polymers which employs a reaction medium capable of addressing the above difficulties.